A mini loudspeaker is an important acoustic component of a portable electronic device for achieving conversion between electrical signals and sound signals, and thus is an energy conversion device. A conventional mini loudspeaker generally includes a shell, which is generally formed by jointing at least two shell bodies, and a vibration system and a magnetic circuit system are received in a space defined by the shell bodies together. In order to ensure the acoustic performance of the mini loudspeaker, the shell bodies should not only be fixedly jointed but also be sealed. At present, the sealing between the two shell bodies is achieved generally by ultrasonic welding or adhesive sealing.
With the miniaturization of the portable electronic device, mini loudspeaker, as a main acoustic component of the portable electronic device, is becoming smaller and smaller accordingly. With the volume of the shell of the mini loudspeaker becoming smaller and smaller, some shell bodies may have no space for arranging an ultrasonic wire for ultrasonic sealing. Therefore, it is more and more difficult to achieve sealing between the two shell bodies. Besides, sealing by the conventional ultrasonic welding or adhesive sealing may cause the following drawbacks.
As shown in FIG. 1, two shell bodies 100 are bonded and sealed by a sealant 102, and the sealant 102 may overflow towards both inside and outside of the shell bodies. As shown in FIG. 2, the two shell bodies 100 are sealed by the ultrasonic welding process, during which the melted ultrasonic wire 104 may also overflow towards both inside and outside of the shell bodies. In the case that the sealant and the melted ultrasonic wire overflow to the inside of the shell bodies, the volume of an inner chamber of the mini loudspeaker may be reduced, therefore, the acoustic performance of the mini loudspeaker and installation positions of the internal components may be adversely affected. In the case that the sealant and the melted ultrasonic wire overflow to the outside of the shell bodies, it may adversely affect the appearance of the mini loudspeaker, to locally increase the external dimension of the mini loudspeaker, thereby adversely affecting the assembly of the mini loudspeaker in the portable electronic device.